Condensed Consolidated Balance Sheet (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 11,149	$ 7,651
Trade accounts receivable, net	440,755	351,187
Prepaid expenses and other	56,247	103,807
Total current assets	508,151	462,645
Property and equipment, at cost	2,479,869	2,338,336
Less accumulated depreciation	886,619	858,852
Net property and equipment	1,593,250	1,479,484
Other assets	19,460	19,531
Total assets	2,120,861	1,961,660
Current liabilities:
Current portion of long-term debt	15,000	200,000
Trade accounts payable	270,961	192,103
Claims accruals	36,847	32,641
Accrued payroll	66,100	57,149
Other accrued expenses	34,864	19,191
Deferred income taxes	22,362	8,865
Total current liabilities	446,134	509,949
Long-term debt	649,292	454,207
Other long-term liabilities	42,542	39,480
Deferred income taxes	384,554	385,003
Stockholders' equity	598,339	573,021
Total liabilities and stockholders' equity	$ 2,120,861	$ 1,961,660